The model setup can be used to assess the processes dominant at a land-ocean interface.
Given that O2 concentrations are critical for both the presence of oxide solid phases and suppression of denitrification, and that organic matter addition leads to O2 depletion, simulations can be performed to quantify endmember scenarios.
This can be done in simulations of flow lines (e.g., Steefel and Lasaga 1994, Spiteri et al., in review), but 2 dimensional flow settings and transverse dispersion may be important. Within our setup, we can include these aspects and quantitatively analyze the conceptual models illustrated below.
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Schematic of nitrogen and phosphorus removal processes at the interface between anoxic freshwater and oxic seawater, after Slomp and Van Cappellen 2004.
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The same tools can also be used to mimic site-specific settings. Here, the literature based process parameterization can be supplemented by further experimental work. At the GA Moses Hammock site, B. Porubsky has measured CO2 production rates, and ammonium sorption equilibria as a function of salt concentrations. He also incorporates his experimental findings of nitrate removal processes in our model.
Salt wedge at the land-ocean interface, representative for the porous media properties and pressure heads measured at the Moses Hammock site. The dark rectangles indicate the screening depths of the sampling wells.
Related Publications and Presentations
Porubsky, W., Meile, C., Moore, W., Tuncay, K. and Joye, S. (in prep.): Hammock groundwater flow and biogeochemistry: Field measurements, laboratory assays and predictive modeling.
Spiteri, C., Slomp, C., Charette, M.A., Tuncay, K., and Meile, C. (2008). Flow and nutrient dynamics in a subterranean estuary (Waquoit Bay, MA, USA): field data and reactive transport modeling. Geochimica et Cosmochimica Acta. in press.
Spiteri, C., Slomp, C.P., Tuncay, K. and Meile, C. (2008): Reactive transport modeling of flow and nutrient dynamics in a subterranean estuaries: The effect of flow dynamics and redox conditions on submarine groundwater discharge of nutrients. Water Resources Research 44, W02430. doi:10.1029/2007WR006071.
Presentations & Proceedings
Porubsky, W.P., Hunter, K., Hyacinthe, C., Joye, S.B., Meile, C.: Groundwater flow and nutrient dynamics in coastal hammocks and salt marsh environments: Observations and modeling of biogeochemical patterns. Carl E. Kindsvater Symposium. Atlanta, March 2008.
Porubsky, W.P., Meile, C. and Joye, S.B.: Upland to marsh groundwater flow and nutrient dynamics. GCE-LTER annual meeting. Athens GA, March 2008.
Porubsky, W.P., Meile, C. and Joye, S.B.: Using field measurements, laboratory-assays, and modeling to examine flow conditions and variations in groundwater biogeochemistry. Estuarine Research Federation Meeting, Providence, November 2007.
Spiteri, C., Slomp, C.P., Charette, M.A., Tuncay, K. and Meile, C.: Reactive transport modeling of flow and nutrient dynamics in a subterranean estuary (Waquoit Bay, MA, USA). International Conference on Water pollution in natural porous media at different scales (WAPO2), Barcelona (Spain), April 2007.
Porubsky, W.P., Meile, C., Joye, S.B.: Variations in groundwater biogeochemistry and flow on Moses Hammock (Sapelo Island, GA): Field measurements, Laboratory assays and modeling. ASLO meeting, Santa Fe, February 2007.
Porubsky, W.P., Meile, C., Joye, S.B.: Variations in groundwater biogeochemistry and flow on Moses Hammock (Sapelo Island, GA): Field measurements, Laboratory assays and modeling. LTER site meeting, Athens, February 2007.
Spiteri, C., Slomp, C.P., Tuncay, K. and Meile, C. : Modeling biogeochemical processes in subterranean etuaries: The effect f redox conditions on the submarine groundwater discharge of nutrients. 13th Annual Symbosium NSG, Utrecht, November 2006.
Spiteri, C., Slomp, C.P., Tuncay, K. and Meile, C. (2007): Modeling biogeochemical processes in subterranean estuaries: The effect of flow dynamics and redox conditions on submarine groundwater discharge. Proceedings of SWIM-SWICA International Conference, Cagliari, September 2006.
Spiteri, C., Slomp, C.P. and Meile, C. Biogeochemistry of nutrients in a subterranean estuary at the Faculty of Earth and Life Sciences, Department of Hydrology and Geo-environmental Sciences, Vrije Universiteit, Amsterdam, February 2006.
Porubsky, W.P., Meile, C. and Joye, S.B.: Nutrient dynamics in the hammock subsurface: The impact of flow and reactions on coastal groundwater composition. The Academy of the Environment UGA, Ocober 2006.
Meile, C. Groundwater processing at the land-ocean boundaries. Coastal Georgia Colloquium, Savannah, October 2006.
Spiteri, C, Slomp, C.P. and Meile, C.: The effect of flow dynamics and redox conditions on submarine groundwater discharge of nutrients. SWIM-SWIMCA meeting, Cagliari, Italy, September 2006.
Spiteri, C., Slomp, C.P., Meile, C. and Charette, M.A. Nutrient dynamics in the subterranean estuary of Waquoit Bay, NAC8, Veldhoven, April 2006.
Meile, C. Nutrient Processing at the land-ocean interface: Assessing groundwater transformation through reactive transport modeling. SeaGrant Advisory Committee Meeting, Brunswick GA, May 2006.
Porubsky, W.P., Meile, C. and Joye, S. Use of a Reaction Transport Finite Element Model (RTFEM) to examine groundwater biogeochemistry and flow at Sapelo Island, GA. Annual GCE-LTER meeting. Athens GA, March 2006.
